Sabermetricians have become fluent in things like park factors, xFIP, ISO, BABIP, UZR and so on and so forth. You could put any three capital letters in succession and it probably means something in baseball statistics.

Here's a new statistic for you, pinpointing exactly how overrated players are historically. It's called WAR/ASS, and it has nothing to do with rear ends.

Read on for an explanation of the statistic, its limitations and who it identifies as the most overrated player to ever step on a baseball field.

(Apologies for the nonsensical photos on some of the old-timers. The Upload Photo function isn't working properly.)

Explaining WAR/ASS

USA TODAY Sports

Want to know how to calculate the incalculable?

Take a player's career Wins Above Replacement (WAR) and divide it by his number of All-Star Seasons (ASS). We must emphasize seasons rather than games, because MLB arbitrarily decided to have two All-Star Games each year from 1959-62. Even if the player appeared in both games in that season, it only counts as one season.

The logic behind the statistic is that only the players with the most wins above replacement should be representing their league in the All-Star Game. If a player's ratio is low, it means he was elected to more All-Star games than he deserved—a pretty good definition of being overrated if you ask me.

I'll admit, it isn't perfect. For starters, the All-Star Game only dates back to 1933, so there's no way of knowing just how overrated Honus Wagner and Ty Cobb might have been. However, it's fairly unlikely that you're old enough to remember anything prior to 1933, so that should be OK for this exercise.

It should also be noted that it was more difficult to come by wins above replacement when there were fewer teams in the league to separate the best starting players from the worst ones. A WAR of 3.0 in 1935 is probably worth about 8.0 in 2005, but I'm not comfortable enough with WAR calculations to determine that handicap.

The statistic is also limited in its ability to calculate a rating for players elected to fewer than five All-Star Games. Therefore, we've limited the scope of this ranking to the 278 guys who played in at least five All-Star Games.

Having said all that, let's see which players have received too much love over the years.

One of the biggest problems for Sweeney was the 608 games he spent as a designated hitter.

All other things being equal, it's hard to rack up WAR as a DH. Billy Butler and Robinson Cano put up nearly identical statistics in 2012, but Cano had a WAR of 7.8 at second base while Butler scored just a 3.0 as a DH.

Regardless of if and where he played on defense, it says something that Sweeney averaged just 1.3 WAR per year over the course of his 16-year career. My guess is it's saying that the late 90's and 2000's was a bad time for a clean ballplayer to try to make a living as a slugger.

No. 11: Frankie Hayes

It's the guys like Frankie Hayes that necessitated the use of All-Star Games and WAR as our means of determining who was most overrated.

Unless you're a historian the likes of Jayson Stark, you've probably never heard of Hayes nor can remotely speak to whether he was overvalued by or against his peers.

However, here's what we do know:

Hayes set a still-standing Cal Ripken-esque record of 312 consecutive games as a catcher. For sake of comparison, Miguel Montero started more games than any other catcher in 2012 despite sitting out 16 percent of his team's games.

He needed over 5,000 plate appearances to reach 119 home runs. Again for sake of comparison, BJ Upton has 119 career home runs in 1,002 fewer plate appearances.

Hayes batted .259 and had a career fielding percentage of .978. No catcher logging more than 200 innings in 2012 had a fielding percentage lower than .980. To be fair, though, the equipment is just the slightest bit better today than it was in the 1930s.

No. 10: Joe Carter

Rick Stewart/Getty Images

Seasons Played: 1983-1997

Career WAR: 17

All-Star Seasons: Five

Resulting Score: 3.40

When I set out on this endeavor, I expected Joe Carter would be the most overrated player in the history of baseball. Funny things like that happen when you hit perhaps the most memorable home run of an entire decade.

That blast off of Mitch Williams in the 1993 World Series was the end of his career as an effective ball-player, but he would get voted to another two All-Star Games after that. This despite compiling a WAR of minus-2.8 over his final five seasons in the league.

He certainly wasn't a one-hit wonder—Carter averaged 30 home runs per season between 1986 and 1996—but he was a below-average player when he wasn't hitting moon shots. Carter had a career batting average of .259 and fielding percentage of .977 (those are bizarrely identical to the numbers we just saw from Frankie Hayes).

He may live on forever in Toronto lore and may never be welcome back in the state of Pennsylvania, but by the numbers, he's the 10th most overrated player of all time.

No. 9: Larry Bowa

Larry Bowa was a light-hitting, soft-handed, slightly speedy shortstop. He was elected to five All-Star Games by virtue of being on the right team at the right time.

That's the only possible explanation for it.

In 9,103 career plate appearances, he batted .260 with 15 home runs and 318 stolen bases. By comparison, Chone Figgins batted 17 points better, stole 19 more bases and hit 20 more home runs in nearly 4,000 fewer plate appearances. That's right—Chone Figgins was better on offense in every aspect than a five-time All-Star.

Bowa had a better-than-average glove, winning Gold Gloves at shortstop in 1972 and 1978. But he was no Ozzie Smith, which was made abundantly clear when Smith came onto the scene in 1980 and ensured Bowa never sniffed an All-Star Game or Gold Glove again.

No. 8: Frank Malzone

Despite averaging just 11.1 home runs per season, the opening sentence in Malzone's Wikipedia bio identifies him as a "right-handed slugger."

Far be it from me to accept Wikipedia as gospel, but we need to take a few leaps of faith when dealing with guys who retired 20 years before I was born. Perhaps it says something about his lofty standing with the fans of Boston if "slugger" is one of the first things to be said about him.

Clearly his added value was on defense, as he won history's first three Gold Gloves for a third baseman before handing over the reins to Brooks Robinson.

Only once in his 12-year career did he accumulate a WAR of more than 3.0, but that didn't stop him from being elected to eight All-Star Games in six seasons.

No. 7: Closers in General

If it's hard to rack up wins above replacement as a designated hitter, it's darn near impossible to do it as a closer.

There are a grand total of nine closers in the bottom 31 in WAR/ASS.

Mariano Rivera is probably the greatest closer we'll ever see, but it has only led to a career WAR of 38.6. Divided by 12 All-Star seasons, it leaves him with a score of 3.22. Very similar things could be said about Trevor Hoffman, Rollie Fingers, Goose Gossage, Lee Smith and Billy Wagner.

However, I'm not ready to say that those guys are specifically overrated. In fact, it would be borderline insane to say that Rivera is one of the 10 most overrated players in MLB history.

What I will say is that closers in general are vastly overrated, and I can't imagine many would disagree with that.

Certainly, it's better to have a great closer than an awful closer. It doesn't take a rocket scientist to know that you're in better hands with Mariano Rivera than you are with John Axford. But even in his best seasons, Rivera is going to blow a handful of saves while Axford is going to record a save in the vast majority of his opportunities.

It's a silly statistic that's overblown by fantasy baseball and the idea that there's such a thing as a "clutch" gene. At least WAR has figured out that even the greatest closers are only worth about two more wins per season than their eighth-inning counterparts.

No. 6: Sandy Alomar Jr.

Rich Pilling/Getty Images

Seasons Played: 1988-2007

Career WAR: 13.7

All-Star Seasons: Six

Resulting Score: 2.28

When he actually played, I seem to remember Sandy Alomar Jr. being pretty good.

Then again, there's a very real possibility that I'm confusing his physical career with how good he was in Major League Baseball Featuring Ken Griffey Jr, which was released in May 1998—the year after what was unequivocally Alomar's best season in the majors.

That game is also solely responsible for my belief that Charles Nagy should have been a unanimous first-ballot Hall of Famer.

Either way, Alomar had difficulties staying on the field. Twenty years as a catcher is nothing to scoff at, but he had more All-Star seasons (six) than he had seasons in which he played 90 or more games (five).

Only once in that 20-year career did he record a WAR of 2.5 or better, which can probably be attributed to all of those seasons effectively spent as a platoon player.

Alomar finished his career with just 112 home runs, failing to hit more than seven in any of his final 10 seasons.

No. 5: Jim Hegan

Welcome to the list of guys you've probably never heard about in your lifetime.

Most of the guys to this point in the list had questionable career stats, but you could at least understand how they might have been considered All-Stars for a portion of their career.

In no way can I figure out what the allure around Hegan might have been.

Save for his rookie season in which he made just 53 plate appearances, he never once batted .250 in a season, finishing his career with a .228 average.

He was an All-Star in 1947 and again from 1949-1952, even though 1948 was the only season in which he recorded a WAR of better than 1.5. That year, he set a career high in home runs (14) and steals (six).

Suffice it to say, those don't feel like valid career-high numbers for a five-time All-Star.

Voters at the time must have attributed the success of the Indians pitching staff to the poor-hitting catcher. Hegan was on the receiving end of three no-hitters in his career, but I fail to see how that warrants multiple trips to the mid-Summer classic.

No. 4: Cookie Rojas

Matthew Stockman/Getty Images

Seasons Played: 1962-1977

Career WAR: 6.9

All-Star Seasons: Five

Resulting Score: 1.38

Let's start out with a fun stat about Cookie Rojas—in 1968, he was a catcher for the Phillies for a grand total of one-third of an inning, allowing a passed ball on one of the only pitches he was expected to catch.

Cookie's career value-added stats are downright comical.

As a batter, his park-adjusted runs "above" average was minus-129.7. I suppose that's to be expected when you have a career batting average of .263 and an ISO (slugging minus batting average) of 0.74.

No. 3: Don Kessinger

Brian Kersey/Getty Images

Seasons Played: 1964-1979

Career WAR: 7.8

All-Star Seasons: Six

Resulting Score: 1.30

Don Kessinger's career numbers make Cookie Rojas look like a sultan of swat.

Kessinger hit just 14 home runs in his 16-year career—one for every 609 plate appearances. He batted just .252 for his career with an ISO of .060. Clearly, slugging was not his strong suit. He wasn't particularly fleet of foot, either, having success in just 100 of his 185 career stolen base attempts.

He did amass two Gold Gloves early in his career, but wound up with a career fielding percentage of just .965—meaning he was good for an error on one out of every 30 plays.

Remember those poor runs "above" average that we noted for Rojas on the last slide? That he cost his team 191 runs over the course of his career? Well, Kessinger was even better; by which I mean he was worth minus-324 runs above average.

I'm not even remotely sure how that is calculated, but it means having a replacement level guy instead of Kessinger would be worth 20 more runs per season.

Despite all that, Kessinger was intentionally walked 69 times in his career, including 18 free passes in 1973 alone.

No. 2: Bobby Richardson

Despite being just barely above replacement level over the course of his career, Bobby Richardson spent more seasons as an All-Star than he did without that honor.

Not only was he elected to eight All-Star games in seven different seasons, but he was the MVP of the 1960 World Series—the first and only World Series MVP from the losing team.

(Two All-Star games per season and an MVP from the losing team? Man, baseball was weird in the early '60s.)

Richardson also won five Gold Gloves, his superb infield defense being the primary cause of all his accolades.

In only three of his 12 seasons did he have a WAR of 0.7 or better. It didn't matter, though. The Yankees were winning multiple World Series and Richardson was a staple at the top of their lineup year in and year out. Voters weren't concerned that he only batted .266 with 34 home runs in his career.

No. 1: Rollie Hemsley

Seasons Played: 1928-1947

Career WAR: 3.4

All-Star Seasons: Five

Resulting Score: 0.68

In case you thought drunk driving was a recent phenomenon among MLB players, type Hemsley's name into Google and you'll find "Rollie Hemsley Alcoholics Anonymous" as one of the first auto-complete options.

At least "Rollicking Rollie" hit something hard in his career, because it certainly wasn't baseballs.

According to his Wikipedia bio, Hemsley's drinking problem was so bad that he was kicked off of four different teams. One has to wonder why teams kept bringing him back, since he never hit more than four home runs in any given season in his career.

Let's do a blind resume comparison:

Player A batted .262 with 31 HR and a WAR of 3.4.

Player B batted .262 with 32 HR and a WAR of 3.6.

Player A is Rollie Hemsley's 19-year career. Player B is Alfonso Soriano's 2012 season. 2012 Alfonso Soriano didn't even finish in the Top 25 among NL Outfielders in All-Star voting. Yet somehow Rollie Hemsley played in five All-Star games.